1. Field of the Invention
This invention relates to heat dissipation systems for electronic device packages. More particularly, it relates to a heat dissipation system having a releasable attachment assembly for releasably securing a heat sink to a heat spreader plate mounted to the electronic device package.
2. Description of Related Art
Many electronic devices and electrical systems such as power controls, switches, variable speed motor controls, microprocessors and the like generate heat during operation. To avoid damage to the device and/or impairment of its operating characteristics, this heat must be dissipated. Accordingly, devices, commonly referred to as "heat sinks", which remove and dissipate excess thermal energy are often necessary to ensure proper operation of electronic devices and other heat-generating systems.
For purposes of the present invention, a heat sink is any body of metal or other thermally conductive material which is placed in thermal contact with an electronic device, device package or other heat-generating system for the purpose of receiving internally generated heat from the device and dissipating the received heat to the surrounding environment by conduction, convection and/or radiation. In order to accomplish this objective, it is generally preferred that heat sinks are constructed of materials having high coefficients of thermal conduction, for example, aluminum, copper and alloys thereof.
A typical heat sink for electrical applications functions by conducting heat away from the heat-generating device and dissipating the heat into the surrounding air. In order for the heat sink to operate efficiently, it must be secured to, or otherwise placed in thermal contact with, the heat-generating component. In the past, various techniques have been used to securedly place heat sinks in thermal contact with electronic devices. For example, it is known to glue or otherwise adhesively mount a heat sink to a predetermined surface of an electronic device, for example, using a heat-conductive epoxy or the like. The art also discloses heat sinks mounted to electronic devices by connective devices, for example, resilient metal clips, screws, bolts and clamps which urge the heat sink and electronic device package into mutual contact.
Technological advances have caused electronic components to decrease in size but increase in power and speed. As a result, therefore, electronic devices occupy less space but tend to generate more heat as a function of surface area. As the electronic devices have less physical structure or surface area for attaching a heat sink to dissipate generated heat, the design of heat sinks has increased in complexity. To provide increased surface area to mount heat sinks in thermal communication with the electronic devices, a heat spreader plate can be used between the heat sink and the electronic device. Such a heat spreader serves to disperse the heat generated by the electronic device throughout a larger physical structure than the device itself, thus allowing a larger heat sink to be mounted in thermal communication with the electronic device via the heat spreader plate. The heat spreader plate also provides a common support structure to which various alternative electronic device packages as well as alternative heat sinks can be mounted using a mounting assembly, socket, or the like.
While the heat spreader plate provides a common support structure, it is highly desirable that the remainder of the assembly which attaches a heat sink to an electronic device be standardized as well. By doing so, flexibility during selection of a heat sink would be greatly enhanced. It is, therefore, the object of the invention to provide a heat dissipation system having a releasable attachment assembly arranged in the manner disclosed herein.